Question

so sanh

3 và 1+\(\sqrt{5}\)

\(\sqrt{7}+\sqrt{15}\) và 7

8 và \(2\sqrt{5}\)

-21 và \(-7\sqrt{10}\)

Answer 1

a) Ta có: \(3=1+2=1+\sqrt{4}< 1+\sqrt{5}\)

b) Ta có: \(7=3+4=\sqrt{9}+\sqrt{16}>\sqrt{7}+\sqrt{15}\)

c) Ta có: \(8=\sqrt{64}\)

\(2\sqrt{5}=\sqrt{4}.\sqrt{5}=\sqrt{20}< \sqrt{64}=8\)

d) Ta có: \(-21=-7.3=-7\sqrt{9}>-7\sqrt{10}\)

Answer 2

`a, 3 = sqrt 4 + sqrt 1 < sqrt 1 + sqrt 5`.

`b, sqrt 7 + sqrt 15 < sqrt 9 + sqrt 16 = 7`.

`c, 2 sqrt 5 < 2 sqrt 16 = 8`.

`d, -7 sqrt 10 < -7 sqrt 9 = -21`..